Imagine an alien world teeming with exotic organisms; verdant ecosystems and advanced megafauna.

On this planet life emerged twice, billions of years ago. Present day, roughly half of plants and animals are of carbon-based descent (as an example), the other half stem from silicon-based ancestors (as another example).

Crucially, on this planet carbon-based life cannot consume silicon-based life for nourishment, nor vice versa.

My question is, with the above in mind, what unique ecological worldbuilding would be possible for these dual biospheres; what adaptations, niches and other interesting features could emerge for life on this planet that wouldn't be possible for the homogenic biosphere on earth?

This is not an idea I've seen elsewhere, so I'd love to hear ideas for fleshing out this concept. :)

Edit: To clarify, the specifics of biochemistry isn't important. The core of the question is how the ecology could be different if half/plants and animals could not gain nutrients from the other half of animals/plants. If unclear, assume organisms analogous to earths'.

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    $\begingroup$ The real question is what's the temperature range on a world where both carbon-based life and silicon-based life can thrive. Hint: silanes are highly volatile (and unstable) at temperatures where water is a liquid. $\endgroup$ – AlexP Jun 22 '17 at 14:26
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    $\begingroup$ I like the idea, but currently this question is too broad. First of all, silicon-based life is not something that does actually exist. You need to clarify what you mean by that chemically and how your organisms work biologically. I think without that information, any direct answer will be complete fantasy. Second of all, you should be more specific as to what you are asking $\endgroup$ – Raditz_35 Jun 22 '17 at 14:33
  • $\begingroup$ Welcome to WorldBuilding Fred! If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$ – Sec SE - clear Monica's name Jun 22 '17 at 14:34
  • $\begingroup$ @AlexP temperature is not the problem here. Maybe you got confused by "Most silylenes are unstable at normal temperature" in that article. Oxygen and water on the other hand could be more problematic $\endgroup$ – Raditz_35 Jun 22 '17 at 14:35
  • $\begingroup$ Hello Fred, and welcome to worldbuilding. I am sorry but I have to put a close vote on your question because 1) it is extremely broad 2) it is entirely opinion based since no-one knows if silicon based life can even exist 3) this is not a question to solve a problem, it is a request for idea-generation. $\endgroup$ – MichaelK Jun 22 '17 at 14:40

There are a few difficulties with this question, all mentioned in the comments to it.

I think however, that there is a reasonable answer we can deduce from your constraints:

We have two lifeforms, that are not only based on completely different (bio)chemical principles. Additionally they also don't really interact with each other: if they can't consume each other, it doesn't make evolutionary sense that they would interact otherwise.

The easiest explanation for this would be, that they have completely different habitats (meaning they never encountered each other). A tidally locked planted/moon comes to mind, or maybe something like surface & underground or ocean dwellers.

The other possibility - that they share habitats but don't really interact much - is less probably and I currently can't think of a good reason to rationalise it.

In any case things would get interesting once a life form from on (or both) ecosystems developed intelligence or rather curiosity and starts exploring the other.


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